22/10/2025
🩸 Is it safe to wait until the haemoglobin levels are lower before giving a transfusion, in order to give fewer transfusions overall?
Blood is a limited resource and transfusion is not risk-free, they should only be given when necessary. So, blood transfusions are often given to people with low levels of haemoglobin, the part of the blood that carries oxygen.
This Cochrane review looked at whether it is safe to wait until haemoglobin drop to lower levels before giving a transfusion, rather than transfusing earlier at higher levels.
For most adults and children, waiting until haemoglobin is lower does not increase the risk of death, heart attack, stroke, pneumonia, blood clots, or infection. This means fewer people receive transfusions unnecessarily.
However, some groups (such as people with brain injuries) may do better if their haemoglobin is kept higher. More research is needed, especially on outcomes beyond survival, such as quality of life or brain recovery.
Find the full Cochrane review in the comments below 👇
